Polybenzoxazole resins and polyimide resins having high heat resistance, excellent electrical and mechanical properties and the like have been used for a surface protective layer or an interlayer insulating layer for a semiconductor chip. For simplifying a process using a polybenzoxazole or polyimide resin, there has been used a positive photosensitive resin composition in which a diazoquinone compound of a photosensitive material, is combined with such a resin (patent document 1).
Such a positive photosensitive resin composition must be heated, after patterning, at a temperature of 300° C. or higher in its use for cyclizing a resin component. However, as semiconductor chip interconnections have been recently finer, the problem of generated thermal damage to a semiconductor chip has been prominent in heating at the high temperature. There have been, therefore, investigations for cyclizing a resin component at a lower temperature, but it is known that a cyclizing rate is reduced if heating temperature for cyclizing is simply lowered, leading to problems in subsequent processes.
There has been investigated, as a method for cyclization at a low temperature, the use of an acid catalyst such as a sulfonic acid and an onium salt.
Meanwhile, recent size reduction of semiconductor chip, acceleration of multilayering of interconnections with higher integration and shift to chip size package (CSP), wafer level package (WLP) or the like have resulted in treatment of wafers with various chemicals in their processing. In these new packages, there has been shifted to the use of a bump instead of conventional wire bonding.    [patent document 1] Japanese Laid-open Patent Publication No. 11-54934